Số hạng u2023 bằng

D

Ta có \(\left\{ \begin{array}{l}{u_3} + {u_1} = 10\\{u_6} + {u_4} = 80\end{array} \right.\)\( \Leftrightarrow \left\{ \begin{array}{l}{u_1}{q^2} + {u_1} = 10\\{u_1}{q^5} + {u_1}{q^3} = 80\end{array} \right.\)\( \Leftrightarrow \left\{ \begin{array}{l}{u_1}\left( {{q^2} + 1} \right) = 10\\{u_1}{q^3}\left( {{q^2} + 1} \right) = 80\end{array} \right.\)\( \Leftrightarrow \left\{ \begin{array}{l}{u_1}\left( {{q^2} + 1} \right) = 10\\10{q^3} = 80\end{array} \right.\)\( \Leftrightarrow \left\{ \begin{array}{l}{u_1} = 2\\q = 2\end{array} \right.\).

Khi đó u2023 = u1.q2022 = 2.22022 = 22023.